How about a STABmons tournament?
This is basically a standard OU tournament with a catch:
Pokemon can get ALL moves that they get STAB from in addition to their regular moves.
Thundurus-T (M) @ Life Orb
Trait: Volt Absorb
EVs: 252 SAtk / 4 SDef / 252 Spd
Modest Nature (+SAtk, -Atk)
- Hidden Power [Ice]
Breloom's Hi Jump Kick is gonna hurt. How about Kyurem-B's access to Icicle Crash and Spear sound like? Landorus-T's Brave Bird? Gliscor getting Stealth Rock and Spikes? Alakazam's Psystrike? How about Keldeo's Water Spout? The possibilities are endless.
Another rule is:
If a Pokemon changes type when evolving, the fully evolved form can get all the moves that the prevolved form's type was.
So Bellossom, which evolves from Gloom, can get every Grass move, like Spore, in addition to every Poison move, like Gunk Shot. Same goes for Scizor, which can get all Flying moves.
To make it less of an OU feel:
Round 1 will be NU.
Round 2 will be RU.
Round 3 will be UU.
Round 4 will be OU.
Standard stuff is banned from Smogon. Banned Pokemon will be announced later on.